Diode Resistance Resistance opposes the flow of current through a device. Diode resistance is the effective opposition a diode offers to current flow. Ideally, a diode offers zero resistance when forward biased and infinite resistance when reverse biased. However, no device is perfect. Practically, every diode has small resistance when forward biased and significant resistance when reverse biased. We can characterize a diode by its forward and reverse resistances.Forward ResistanceEven with forw